1. Field of the Invention
The invention relates to a process for the preparation of organosilicon compounds containing urethane groups, and to organosilicon compounds having urethane groups prepared thereby.
2. Background Art
U.S. Pat. No. 5,001,210 A discloses the preparation of a polyurethane by a two-stage process. In a first stage, a diamine of the formula A-M-A, in which A is a terminal amino group and M is a radical desired to be introduced into the polyurethane, such as a hydrocarbon radical or a polymer radical, e.g. a dimethylpolysiloxane radical, is reacted with a cyclic carbonate to give a urethane diol. The polymer is then synthesized by reacting the urethane diol obtained in the first stage with a diisocyanate to obtain the desired polyurethane. A disadvantage is that the chain length achievable in the polymer synthesis is limited by impurities and inexact stoichiometry of the starting materials.
U.S. Pat. No. 6,379,751 A describes water repellents for the treatment of leather, wherein the water repellants, fixed with formic acid, have the same effectiveness as with conventional fixing with chromium salts. The water repellants described therein contain a polysiloxane which contains carboxyl groups and is prepared by reacting an aminopolysiloxane with a lactone or a cyclic carbonate, and the hydroxyl groups in the polysiloxane obtained in the reaction are then reacted with a polycarboxylic acid derivative. A further synthesis to give high molecular weight polymers is not described.
U.S. Pat. No. 5,174,813 and U.S. Pat. No. 5,389,364 disclose reaction products of linear aminopolysiloxanes with carbonates or lactones. The aminosiloxane derivatives are used in U.S. Pat. No. 5,174,813 without a further condensation process in polish formulations and in U.S. Pat. No. 5,389,364 in hair care compositions.
U.S. Pat. No. 5,686,547 describes a process for the preparation of silicones having hydroxycarbamate functional groups, in which hydrogensiloxanes are subjected to an addition reaction with unsaturated cyclic carbonate esters in a hydrosilylation reaction, to obtain silicones having carbonate functional groups which are subsequently reacted with organic amines such as dialkylamines. Aminopolysiloxanes are not used.